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Prousalis KP Polygenis DA Syrokou A Lamari FN Tsegenidis T 《Analytical and bioanalytical chemistry》2004,379(3):458-463
An efficient analytical method is presented involving effective sample clean-up with solid-phase extraction and HPLC-UV analysis for the simultaneous determination of carbendazim, thiabendazole, and o-phenylphenol residues in lemons. Sample preparation involves extraction with acetonitrile acidified with trifluoroacetic acid and an ethyl acetate/petroleum ether mixture. Purification of the crude extract was carried out with liquid–liquid partitioning after addition of an aqueous ammonia solution. Final clean-up was performed on polymeric reversed-phase cartridges pretreated with sodium dodecyl sulfate. Chromatographic analysis was performed on a reversed-phase HPLC column isocratically eluted with an acetonitrile/water/ammonia mixture and UV detection at 254 nm. The chromatographic method is repeatable, reproducible, and sensitive. Fungicide recoveries from lemon samples fortified at levels of 5 and 1 mg kg–1 were 81–85% for carbendazim, 96–98% for thiabendazole, and 81–106% for o-phenylphenol with coefficients of variation of 2.5–7.4%. Detection limits for carbendazim, thiabendazole, and o-phenylphenol in lemons were 0.21, 0.27, and 0.51 mg kg–1, respectively. 相似文献
2.
Konstantinos P. Prousalis Gerasimos M. Tsivgoulis 《International journal of environmental analytical chemistry》2013,93(13-14):1065-1078
With the aim of developing polyclonal antibodies binding as many phenyl-N-methylcarbamate insecticides (PNMCs) as possible, IgY antibodies were produced in laying hens. Two haptens (3-(2,6-dimethyl-4-(methylcarbamoyl)phenylaminocarbonyl)propanoic acid and 4-((2,6-dimethyl-4-(methylcarbamoyl)phenylaminocarbonyl)-3,3-dimethyl)butanoic acid) were synthesized preserving the major structural features of PNMCs, by a novel synthetic pathway. These haptens differed only in the spacer arm incorporated. Immunizing antigen and coating antigen were prepared by coupling the first hapten with bovine serum albumin and the second with thyroglobulin, from porcine thyroid glands, respectively. The titre and maturation increase in the developed antibodies, in the egg yolk, were assessed by non-competitive ELISA. Avidity and cross-reactivity of the antibodies with selected pesticides were estimated by means of competitive ELISA. The produced IgYs exhibited a high binding capacity to carbaryl, trimethacarb, metolcarb, aminocarb, and promecarb. These antibodies can be used for immunosorbent preparation for analytical purposes. 相似文献
3.
Clusters of galaxies are excellent probes of cosmic structure and evolution. X-ray studies of clusters provide some of their
key parameters, viz., temperature of the hot intra-cluster gas, its metallicity, X-ray luminosity and surface brightness giving
mass distribution and mass-flow rate in the case of cooling flows. X-ray measurements for a large sample of clusters have
lead to estimates of the total gravitating mass in them, which can be compared to the virial masses derived from dynamical
considerations and gravitational lensing in some of them. X-ray derived total masses are consistent with masses obtained from
the other methods after the effects due to the presence of cooling flows are taken into account in the analyses. Estimated
virial masses, lack of evolution in X-ray properties, and detection of several very hot clusters at high redshifts indicate
a Universe with a low value (≤ 0.3) for the Ω parameter. 相似文献
4.
Dimitrios A. Prousalis Christos K. Volos Ioannis N. Stouboulos Ioannis M. Kyprianidis 《Nonlinear dynamics》2017,90(3):1681-1694
In this research work a novel 4-D memristive system is presented. The proposed system belongs to the category of dynamical systems with hidden attractors as it displays a line of equilibrium points. Also, it has an hyperchaotic dynamical behavior in a particular range of its parameters space. System’s behavior is investigated through numerical simulations, by using well-known tools of nonlinear theory, such as phase portrait, bifurcation diagram, Lyapunov exponents and Poincaré map. Next, the case of chaos control of the system with unknown parameters using adaptive control method is investigated. Finally, an electronic circuit realization of the novel hyperchaotic system using Spice is presented in detail to confirm the feasibility of the theoretical model. 相似文献
5.
Half life for the emission of exotic clusters like 8Be, 12C, 16O, 20Ne, 24Mg and 28Si are computed taking Coulomb and proximity potentials as interacting barrier and many of these are found well within the
present upper limit of measurement. These results lie very close to those values reported by Shanmugam et al using their cubic plus Yukawa plus exponential model (CYEM). It is found that 12C and 16O emissions from 116Ce and 16O from 118Ce are most favorable for measurement (T
1/2<1010 s). Lowest half life time for 16O emission from 116Ce stress the role of doubly magic 100Sn daughter in exotic decay. Geiger-Nuttall plots were studied for different clusters and are found to be linear. Inclusion
of proximity potential will not produce much deviation to linear nature of Geiger-Nuttall plots. It is observed that neutron
excess in the parent nuclei slow down the exotic decay process. These findings support the earlier observations of Gupta and
collaborators using their preformed cluster model (PCM). 相似文献
6.
Shashwati Sen DK Aswal Ajay Singh TV Chandrasekhar Rao KP Muthe JC Vyas LC Gupta SK Gupta VC Sahni 《Pramana》2002,58(5-6):867-870
The MgB2 superconductor, synthesized using solid-state and liquid-phase sintering methods, have been characterized for various properties.
The upper critical field, irreversibility line and critical current density have been determined using magnetization data.
The current-voltage characteristics recorded under an applied magnetic field revealed the existence of vortex glass transition.
The surface analysis using X-ray photoelectron spectroscopy shows that MgB2 is sensitive to atmospheric degradation. 相似文献
7.
Analysis of carbendazim and thiabendazole in lemons by CE-DAD 总被引:1,自引:0,他引:1
C. K. Kaltsonoudis F. N. Lamari K. P. Prousalis N. K. Karamanos T. Tsegenidis 《Chromatographia》2003,57(3-4):181-184
Summary A capillary electrophoretic method for the determination of two benzimidazole fungicides, carbendazim and thiabendazole, in
lemons has been developed. The two fungicides were separated in a law-pH phosphate buffer containing acetonitrile. Reproducibility
tests measuring both migration times and peak areas gave low relative standard-deviation values. Calibration graphs were linear
and the detection limits, defined as a signal-to-noise ratio of 3:1, were 2.3 and 2.0 μg mL−1 for thiabendazole and carbendazim, respectively. Analysis of carbendazim and thiabendazole residues in lemons was performed
after lemon homogenization, extraction with ethyl acetate and purification through a series of separatory-funnel, acid-base
partitions. This lemon clean-up procedure ensured no interference in the capillary electrophoretic analysis from lemon endogenous
ingredients. 相似文献
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